lib/module.c

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  20  * DEALINGS IN THE SOFTWARE.
  21  */
  22
  23 #include "config.h"
  24
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <limits.h>
  30 #include <dlfcn.h>
  31
  32 #include "module.h"
  33 #include "memory.h"
  34 #include "version.h"
  35
  36 DEFINE_MTYPE_STATIC(LIB, MODULE_LOADNAME, "Module loading name")
  37 DEFINE_MTYPE_STATIC(LIB, MODULE_LOADARGS, "Module loading arguments")
  38
  39 static struct frrmod_info frrmod_default_info = {
  40         .name = "libfrr",
  41         .version = FRR_VERSION,
  42         .description = "libfrr core module",
  43 };
  44 union _frrmod_runtime_u frrmod_default = {
  45         .r = {
  46                 .info = &frrmod_default_info,
  47                 .finished_loading = 1,
  48         },
  49 };
  50
  51 // if defined(HAVE_SYS_WEAK_ALIAS_ATTRIBUTE)
  52 // union _frrmod_runtime_u _frrmod_this_module
  53 //      __attribute__((weak, alias("frrmod_default")));
  54 // elif defined(HAVE_SYS_WEAK_ALIAS_PRAGMA)
  55 #pragma weak _frrmod_this_module = frrmod_default
  56 // else
  57 // error need weak symbol support
  58 // endif
  59
  60 struct frrmod_runtime *frrmod_list = &frrmod_default.r;
  61 static struct frrmod_runtime **frrmod_last = &frrmod_default.r.next;
  62 static const char *execname = NULL;
  63
  64 void frrmod_init(struct frrmod_runtime *modinfo)
  65 {
  66         modinfo->finished_loading = 1;
  67         *frrmod_last = modinfo;
  68         frrmod_last = &modinfo->next;
  69
  70         execname = modinfo->info->name;
  71 }
  72
  73 struct frrmod_runtime *frrmod_load(const char *spec, const char *dir, char *err,
  74                                    size_t err_len)
  75 {
  76         void *handle = NULL;
  77         char name[PATH_MAX], fullpath[PATH_MAX], *args;
  78         struct frrmod_runtime *rtinfo, **rtinfop;
  79         const struct frrmod_info *info;
  80
  81         snprintf(name, sizeof(name), "%s", spec);
  82         args = strchr(name, ':');
  83         if (args)
  84                 *args++ = '\0';
  85
  86         if (!strchr(name, '/')) {
  87                 if (!handle && execname) {
  88                         snprintf(fullpath, sizeof(fullpath), "%s/%s_%s.so", dir,
  89                                  execname, name);
  90                         handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  91                 }
  92                 if (!handle) {
  93                         snprintf(fullpath, sizeof(fullpath), "%s/%s.so", dir,
  94                                  name);
  95                         handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  96                 }
  97         }
  98         if (!handle) {
  99                 snprintf(fullpath, sizeof(fullpath), "%s", name);
 100                 handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
 101         }
 102         if (!handle) {
 103                 if (err)
 104                         snprintf(err, err_len,
 105                                  "loading module \"%s\" failed: %s", name,
 106                                  dlerror());
 107                 return NULL;
 108         }
 109
 110         rtinfop = dlsym(handle, "frr_module");
 111         if (!rtinfop) {
 112                 dlclose(handle);
 113                 if (err)
 114                         snprintf(err, err_len,
 115                                  "\"%s\" is not an FRR module: %s", name,
 116                                  dlerror());
 117                 return NULL;
 118         }
 119         rtinfo = *rtinfop;
 120         rtinfo->load_name = XSTRDUP(MTYPE_MODULE_LOADNAME, name);
 121         rtinfo->dl_handle = handle;
 122         if (args)
 123                 rtinfo->load_args = XSTRDUP(MTYPE_MODULE_LOADARGS, args);
 124         info = rtinfo->info;
 125
 126         if (rtinfo->finished_loading) {
 127                 dlclose(handle);
 128                 if (err)
 129                         snprintf(err, err_len, "module \"%s\" already loaded",
 130                                  name);
 131                 goto out_fail;
 132         }
 133
 134         if (info->init && info->init()) {
 135                 dlclose(handle);
 136                 if (err)
 137                         snprintf(err, err_len,
 138                                  "module \"%s\" initialisation failed", name);
 139                 goto out_fail;
 140         }
 141
 142         rtinfo->finished_loading = 1;
 143
 144         *frrmod_last = rtinfo;
 145         frrmod_last = &rtinfo->next;
 146         return rtinfo;
 147
 148 out_fail:
 149         if (rtinfo->load_args)
 150                 XFREE(MTYPE_MODULE_LOADARGS, rtinfo->load_args);
 151         XFREE(MTYPE_MODULE_LOADNAME, rtinfo->load_name);
 152         return NULL;
 153 }
 154
 155 #if 0
 156 void frrmod_unload(struct frrmod_runtime *module)
 157 {
 158 }
 159 #endif